UPDATE: This issue is resolved. Known good calipers and carriers from
@J-SPEC did the trick. I believe my carrier sliders were toast.
Hi all,
Another post about a mushy brake pedal... I've had 2 new rear calipers, fronts have been refurbished with new pistons and seals, I have bled the brakes to buggery. Literally no air bubbles are coming out and I've probably used well over 3 litres of fluid now. I've got Yellowstuff pads on the front with plenty of life left and Apec pads on the back, also with plenty of life left.
When I drive the car, there is an initial mushyness to the pedal. It goes down and I start to hear the rear brakes grab but I'm not braking until the pedal is well down its travel. If I quickly pump the brakes, a firmness that I expect seems to come in.
I have also noticed under heavy braking that the ABS is triggering way more than I'd expect it to.
Other things:
I have no loss of brake fluid.
The brake fluid is quality and new.
My handbrake seems fine.
When the car is off there is still a bit of initial play in the pedal before it goes firm. It is still firmer as you'd expect with the car off.
Any ideas or suggestions would be really welcome at this point. I've got a track day in a couple of weeks and I need confidence in the brakes.
Edit: Wondering if it could be that rear discs are worn too much?
@shnazzle I know these are potentially quite old? Other thought is ABS module is on its way out... but it is triggering so perhaps not?
Potential issues:
Pads are compressing
Air in the ABS pump
Master cylinder is drawing in air
Brake servo is on its way out
Leak on the brake servo line
Calipers haven't been rebuilt properly
If it pumps up, it's got air in it.
Check for sticky brake sliders on the front. Rear pad nipple is in the recess too I take it?
Quote from: Anon on January 5, 2023, 16:44Have you tried bleeding it with the engine running so the ABS module is powered up ? I had a very similar problem with my dads RAV4 about a year ago after doing new brake lines to the back of the car. I think some of the valve block or accumulator doesn't bleed properly unless it is powered up. This is a blind stab in the dark. But he had failed to get the bleed worthy after quite a while... then I started it up and he pressed the pedal while I did the bleed nipples, and within minutes the pedal was bang on.
I can see me trying that. I have forgotten what my own thread was. But would just like that bit more firmness right from the off.
If I want it to stop, it stops. But I wonder some times if it was designed that way. Initial soft and gentle for 80% of the time. Day to day use. But will have your nose pressed against the screen if you really ask.
As an amateur driveway spanner spinner. I will have to jack and remove each wheel in sequence. I take it, it should not matter if the engine is off between each wheel. Just so long as its running at the time of bleeding.
I can think of two things.
1. Trapped air behind the pistons that need to find their way to the bleeder screws. It happens in a very dry system that is not bench bled. Sometimes tapping it both the master and calipers might shake it loose.
2. I did replace one caliper on a previous car and could never get the pedal tight as before. Upon further reading from numerous complaints some of these caliper manufactures use grease in the assembly that create this condition from what I read. I do not know how since grease along with the fluid is non compressible but anything is possible. Over time I noticed that the brake fluid would get dirty and it was due to whatever grease was added.
In addition to this a local member replaced all of his calipers with refurbish ones from the same company I bought and experienced a worse situation where no amount of bleeding fixed it.
I do not know the reason but I would suspect the remans.
After that experience I decided that if I ever need a caliper I would buy one from a low millage wrecker or new OEM.
Thank you everyone for the suggestions.
I've gone round, tapped on everything, re bled again with engine off and on. All calipers are moving freely, I even put new rear pads in.
Result: a slightly improved brake pedal, which I think is from the new pads. However there is still an initial mushyness/dead travel. The pedal hardens quicker, it takes one pump, not two.
Unless there is *still* air in the system I'm thinking master cylinder on its way out?
I'm loathe to take it to a garage as I've read of stories where they're unable to sort it. Plus I like to do all the work myself. But this may be a last resort...
Oh yes and I hope I'm not going to need a full set of calipers. The problem was there before I refurbished the fronts anyway. It appeared after a track day when everything was working fine before.
Have you replaced all your fluid?
Just wondering whether you've boiled your fluid, in which case a full flush is the only way forward. As you said it was after a track day
Quote from: shnazzle on January 7, 2023, 15:28Have you replaced all your fluid?
Just wondering whether you've boiled your fluid, in which case a full flush is the only way forward. As you said it was after a track day
Replaced several times :)
Quote from: MrChris on January 7, 2023, 15:36Replaced several times :)
That's not it then.
Is there a hissing sound when you press the brake?
Wondering if it's the brake booster. Significantly cheaper than pump
Seldom (if ever mentioned) in relation to car / brake hydraulic systems but air can be entrained in the brake fluid if carelessly poured into the reservoir.
As said, not read of it to do with car systems but larger hydraulic systems where oil is poured from eg 25L drums into a reservoir air can certainly get entrained and is best left to settle out before proceeding.
When all else fails ?
Quote from: Anon on January 7, 2023, 16:53I've been in the diagnostic game for over a decade
Thanks Anon I like what you're saying here. And as
@Carolyn says if pumps then there's air. I guess there's still air. I will try and bleed the master cylinder per the Toyota manual, I'll get the rear end as high as possible and do another bleed. As I said, it's definitely better so it must just be a trapped bubble or something.
Quote from: shnazzle on January 7, 2023, 16:05That's not it then.
Is there a hissing sound when you press the brake?
Wondering if it's the brake booster. Significantly cheaper than pump
Definitely not the booster, at least none of the symptoms when I google/YouTube the issues associated with brake boosters i.e. no hissing etc.
Quote from: Anon on January 7, 2023, 16:53And also always bleed out the master cylinder first by doing the bleed by opening the flare nuts on the ABS module that come from the master cylinder. Give them a few pump purge outs first, then work your way down the path.
I take it by using this option. You can do it yourself without need for a 2nd person. Just a rag to catch the fluid.
Vs, the manual suggested way of disconnecting the pipes at the master cylinder end and covering the holes with your fingers in sequence as someone else operates the pedal.
As mentioned previously,I first bled brakes in the early '60's, first with a jar and tube, then with automatic valves but then with
Automatic Brake or Clutch Bleed Tube [PWN189] 25cm Long Rubber Bleeding tube.
Many company cars later and the need to bleed brakes for myself again I bought another.
Saves me needing to shout at Mrs J. Neither method has ever failed for me, but the split tube is a very simple device, it has been available to buy, to my knowledge for 60 years, so, just maybe it has some credentials.
Hi all, thought I'd update on this more out of courtesy than anything.
The brake pedal is "good enough" for now. I've basically got very little time to get out and bleed the brakes, but I consider them to be fine. I'll hopefully get a chance to do another bleed before my next track day where I'll look to also bleed the ABS unit as per Anon recommendation above.
As ever I believe
@Carolyn was originally on the money. It has to just be air in the system. I can't see any symptoms to do with booster or the master cylinder (there's no way I have the time to swap this out to check though).
Strangely as the car has sat for a few days the pedal seems slightly better... maybe this is air working its way to somewhere it's not as noticeable?
Anyway, the saga will continue I'm sure.
@Mr Chris
Thank you for the update.
Thread revival...!
As per my post in January the pedal has been "good enough". It was also fine for my last track day, though in the last week the mushy pedal has come back with a vengeance.
Bled the master cylinder (fine).
Bled the ABS module (some small bubbles came out of one of the lines).
Bled the rear brakes (completely fine).
Bled the passenger front caliper: full of bubbles.
Went for a test drive, seemed okay but then then mushy pedal came back. Checked the front left again and bubbles had come back. I'm guessing my caliper rebuild has not stood the test of time. The calipers were fairly well corroded in places.
Edit: I should also note that when I'm stationery and I let go of the brake pedal I can hear the brakes sort of "sighing" as they release (kind of like they're releasing slowly). Again, feel like this is a caliper problem.
So just before I order 2 new/refurb calipers for the front. This is a dodgy caliper right? Probably the seals not seating properly and letting air in?
Edit 2: Two Pagid Calipers ordered :D
Quote from: MrChris on March 6, 2023, 08:50Thread revival...!
As per my post in January the pedal has been "good enough". It was also fine for my last track day, though in the last week the mushy pedal has come back with a vengeance.
Bled the master cylinder (fine).
Bled the ABS module (some small bubbles came out of one of the lines).
Bled the rear brakes (completely fine).
Bled the passenger front caliper: full of bubbles.
Went for a test drive, seemed okay but then then mushy pedal came back. Checked the front left again and bubbles had come back. I'm guessing my caliper rebuild has not stood the test of time. The calipers were fairly well corroded in places.
Edit: I should also note that when I'm stationery and I let go of the brake pedal I can hear the brakes sort of "sighing" as they release (kind of like they're releasing slowly). Again, feel like this is a caliper problem.
So just before I order 2 new/refurb calipers for the front. This is a dodgy caliper right? Probably the seals not seating properly and letting air in?
Edit 2: Two Pagid Calipers ordered :D
Sure that's not the brake booster leaking?
But I guess if bubbles keep appearing then it is indeed letting in air somewhere, but...then surely it would also be leaking fluid from that same spot?
Quote from: shnazzle on March 6, 2023, 11:51Sure that's not the brake booster leaking?
But I guess if bubbles keep appearing then it is indeed letting in air somewhere, but...then surely it would also be leaking fluid from that same spot?
Err no not sure of that to be honest with you. I thought the brake booster would result in difficult to press brakes pretty much all the time. Plus the squishyness is also there when the engine is off - as in: pump once, and it's solid.
Caliper is not leaking at all. I figured that as I press the brakes the seal could be moving in such a way that air gets dragged in. When I release the brakes, it seals it therefore stopping it leaking? I have no idea, as I've run out of ideas tbh...
Both front calipers were a bit crusty when I refurbed them and I'm not convinced of my ability to refurb, so figure I might as well get properly refurbed ones so have gone for Pagid ones off ECP for about £100 each.
I'm basically working my way back to the master cylinder. It could still be the MC but at least I've known good working order parts before I get to it...
The master brake cylinders on this car are generally trouble free and virtually no reported issues or replacements from the history of ownership from a large number of cars. Calipers on the other hand either rebuilt using various kits or remanufactured have had issues. It's not to say a rebuilt caliper will fail but it's highly probable depending on the condition.
In todays market I would buy good low millage ones from salvage or brand new OEM.
Quote from: Dev on March 6, 2023, 15:59In todays market I would buy good low millage ones from salvage or brand new OEM.
Already purchased the refurbed Pagid calipers. I figured spending a bit more than the less well-known brands should give better quality...?
This brake issue is just absolutely doing my head in to be honest. I've seen a number of other posts on the forum with squishy/spongey brake pedal feel and I've not found any thread that resolves the issue.
I've found threads where people have replaced calipers and it still hasn't resolved the issue so I hope I'm not throwing money at the wrong part but... the calipers are old and my DIY refurb job probably wasn't the best (due to corrosion remaining where the seals go).
I know the brakes work VERY well because once I get past the initial pump required to firm up the pedal, the car stops on a dime.
Quote from: MrChris on March 6, 2023, 16:20Already purchased the refurbed Pagid calipers. I figured spending a bit more than the less well-known brands should give better quality...?
This brake issue is just absolutely doing my head in to be honest. I've seen a number of other posts on the forum with squishy/spongey brake pedal feel and I've not found any thread that resolves the issue.
I've found threads where people have replaced calipers and it still hasn't resolved the issue so I hope I'm not throwing money at the wrong part but... the calipers are old and my DIY refurb job probably wasn't the best (due to corrosion remaining where the seals go).
I know the brakes work VERY well because once I get past the initial pump required to firm up the pedal, the car stops on a dime.
I have also read the problem with pedal feel but its either user error in the bleed or caliper issues.
I have replaced calipers and brake lines on my car twice. Each time I had no issues with the master running dry and starting the bleed from scratch.
The last time was when I replaced my fronts with Wildwood and did a gravity bleed which is considered not the thing to do with new calipers but it worked. I did have to drive the car and come back for a second bleed to get the last bit of air out.
Having installed a refurbished caliper for my previous Honda I experienced the same issue you are describing. It is like having more pedal travel before it engages but it still locks up the wheels.
I would say there must be something in the refurbishment that is not upto OEM standards because I did multiple bleeds with no luck. I have also driven a members car with the same issues but worse since he replaced all of this calipers from the same referb company that I used for my Honda. That is why I will only use an OEM salvaged caliper from now on because it was extremely frustrating.
Quote from: Dev on March 6, 2023, 16:34I heave also read the problem with pedal feel but its either user error in the bleed or caliper issues.
I have replaced calipers and brake lines on my car twice. Each time I had no issues with the master running dry and starting the bleed from scratch.
The last time was when I replaced my fronts with Wildwood and did a gravity bleed which is considered not the thing to do with new calipers but it worked. I did have to drive the car can come back for a second bleed to get the last bit of air out.
Having installed a refurbished caliper for my previous Honda I experienced the same issue you are describing. It is like having more pedal travel before it engages but it still locks up the wheels.
I would say there must be something in the refurbishment that is not upto OEM standards because I did multiple bleeds with no luck. I have also driven a members car with the same issues but worse since he replaced all of this calipers from the same referb company that I used for my Honda. That is why I will only use an OEM salvaged caliper from now on because it was extremely frustrating.
This thread (https://www.spyderchat.com/threads/really-weird-brake-problem.151021/) on spyderchat (which I think you are in
@Dev) talks about the issue being to do with ABS module (though mine is activating under heavy braking).
I suppose if I get official calipers for the front, I'd also need to go for the rears too... but then plenty of owners go for refurbished calipers and don't have this issue.
I would clamp the rear calipers 1st just to make sure the problem is with the front.
Sticking rear sliders or overly adjusted hand brake cables would also give the same effect.
Quote from: MrChris on March 6, 2023, 16:50This thread (https://www.spyderchat.com/threads/really-weird-brake-problem.151021/) on spyderchat (which I think you are in @Dev) talks about the issue being to do with ABS module (though mine is activating under heavy braking).
I suppose if I get official calipers for the front, I'd also need to go for the rears too... but then plenty of owners go for refurbished calipers and don't have this issue.
Not only was I on that thread I have test driven that owners car.
https://www.spyderchat.com/threads/driving-impressions.138401/page-2
What is not in the posts is my conversation with the owner that told me that he bought the same refurbish brand as my Honda which has the same issues but worse.
If your ABS module is activating then it should be ok. The problem is the weird travel feel in the pedal which I thought was fade from new pads and rotors but I was being too optimistic.
Later on I determined that it must be the refurbished calipers so I gave him for testing my used front calipers that I replaced for my Willwood to test to see if it improved the braking feel. I never heard back from him again.
Quote from: mr2garageswindon on March 6, 2023, 17:15I would clamp the rear calipers 1st just to make sure the problem is with the front.
Sticking rear sliders or overly adjusted hand brake cables would also give the same effect.
Good shout thanks! Any idea how to clamp off braided brake lines though? Wouldn't that damage them?
Quote from: Dev on March 6, 2023, 17:18Not only was I on that thread I have test driven that owners car.
https://www.spyderchat.com/threads/driving-impressions.138401/page-2
What is not in the posts is my conversation with the driver that told me that he bought the same refurbish brand as my Honda which has the same issues but worse.
If your ABS module is activating then it should be ok. The problem is the weird travel feel in the pedal which I thought was fade from new pads and rotors but I was being too optimistic.
Later on I determined that it must be the refurbished calipers so I gave him for testing my used front calipers that I replaced for my Willwood to test to see if it improved the braking feel. I never heard back from him again.
Hmm, sounds like it might be worth cancelling my order of the Pagid calipers and just sourcing some known good calipers or splashing out on new from Toyota (I assume they would be new?).
Quote from: Anon on March 6, 2023, 20:25My Padgid calipers were perfect. New Toyota will be insanely expensive!
I totally support the diagnose your issue first approach by isolating calipers etc.
But yes, you cannot use hose clamps on braided hoses.
Make a stopper with some brake pipe and flairs, that would be my approach.
If your calipers are leaking air, I would expect to see fluid leaking too.
I think you are making this more complicated than it needs to be, its a very primitive hydraulic system. Just isolate bits and see if it works.
Even unbolt the calipers then put G clamps round them, see if the pedal is hard or not etc.
Agree with you that it is more complicated than it needs to be... I just wish I had more time to work on my 2. Doesn't help that it lives outside and not in a garage. Dark nights and rain don't help.
Great idea on using clamps on the calipers, didn't even cross my mind. I'll isolate calipers using this approach next.
Phoned Toyota earlier and calipers are approx. £250 each on the front.
Quote from: MrChris on March 6, 2023, 20:00Good shout thanks! Any idea how to clamp off braided brake lines though? Wouldn't that damage them?
Hmm, sounds like it might be worth cancelling my order of the Pagid calipers and just sourcing some known good calipers or splashing out on new from Toyota (I assume they would be new?).
I suppose it depends on where you are and what works. Maybe a different refurb I don't know but it will never be as good as a factory fresh part were material is removed to refurbish it even if tolerances are acceptable .
Based on my bad experience and the experience of others the clear choice for me if I was in a similar situation again is salvage from a known vehicle with low miles with a 15 to 30 day warranty. I can find them online from reputable salvage yards or even eBay. I did this for a caliper on another car that had 30k miles before it was totaled and the part looked fairly new including the rubber seal. Cleaned it with some brake cleaner and it worked like it should until I sold the car.
I have had greater success with reputable salvage low milage parts because it is the closest thing to OEM without the high cost.
Every time I try a third party part its like rolling the dice but I still do from time to time so it depends.
Here is a nice read I found today. Similar story different day from a different supplier than the ones from the other post. A lot of these remans are garbage.
https://www.spyderchat.com/threads/braking-issues-at-my-wits-end-need-advice.160745/#post-2197465
The problem here is he decided to remedy the situation by buying another set of remans from MWR which sells under their QRP brand which is not very good.
New does not mean remans but I am sure there might be some good ones done right but who really knows what goes into the process to machine them correctly. The attractive low price is not always what it seems.
Thanks
@Dev appreciate the comments.
By way of an update I tried
@mr2garageswindon suggestion of clamping off the front calipers this morning and found one of my carrier bolts rounded out and a slider starting to stick. So I've called up
@J-SPEC and I've got 2 calipers with carriers on order. Then will do another full bleed and I hope I'm there..!
Hopefully you're getting close to sorting this.
You mentioned in your original post:
Quote from: MrChris on January 5, 2023, 14:53I've had 2 new rear calipers, fronts have been refurbished with new pistons and seals
I took this as that you had just recently replaced the rear and refurbished the front calipers and since then the brake pedal was mushy, is my assumption correct?
If it is then logic dictates the issue is related to these parts rather than anything else.
Quote from: MikeBoo on March 11, 2023, 13:49Hopefully you're getting close to sorting this.
You mentioned in your original post:I took this as that you had just recently replaced the rear and refurbished the front calipers and since then the brake pedal was mushy, is my assumption correct?
If it is then logic dictates the issue is related to these parts rather than anything else.
Having replaced the rear and renovated the front calipers on my car, abrading the discs and replacing the part worn pads, in the same relative positions, the pedal did feel
different but not a hydraulic mushiness.
Quote from: MikeBoo on March 11, 2023, 13:49Hopefully you're getting close to sorting this.
You mentioned in your original post:I took this as that you had just recently replaced the rear and refurbished the front calipers and since then the brake pedal was mushy, is my assumption correct?
If it is then logic dictates the issue is related to these parts rather than anything else.
Yep, I replaced the rears with Ridex calipers from Autodoc (and btw through all of this the handbrake is still effective, so I guess that means they're good?!), then I refurbed the fronts myself with new seals and pistons. So yes, logically the parts I refurbished are most likely the weak link. The fact I found the carrier slider to be sub-optimal is likely contributing to the issue, plus I believe air might be getting in somewhere around the caliper too...
Andy at
@J-SPEC confirmed that it's extremely unlikely to be the master cylinder unless it ran dry (it hasn't).
Quote from: Joesson on March 11, 2023, 16:53Having replaced the rear and renovated the front calipers on my car, abrading the discs and replacing the part worn pads, in the same relative positions, the pedal did feel different but not a hydraulic mushiness.
Different how?
@MrChris Like the used pads were bedding in again onto the used discs. I guess they would be in marginally different positions, one to another and so the minute highs and lows were like two corrugated surfaces coming together.
Some, for me, severe use of the pedal was necessary to begin to eliminate that feel.
Having read all the proposals going to more unlikely issues.
Are your bearings okay? If they are not, or something in the assembly is not as it should it could be pad knockback. However, if you experience repeatedly even on straight line most probably is not the culprit. You can also measure the runout on cleaned hub and then on the disc to get a bit more insight.
While I wait for JSPEC calipers and carriers to arrive I found this video I took the other day. If anyone watches it then this is description of what I'm experiencing (all done stationary on my drive):
1. Engine off, foot on brake pedal.
2. Engine starts, pedal depresses and stops.
3. Pump twice and pedal is at expected position (and holds).
4. Couple more pumps then off the brake pedal for extended time.
5. Depress pedal and it goes down quite a bit, followed by a pump and then a second pump: brake is now at acceptable position and feeling good.
6. Repeat step 5 and same results.
7. Hold brake and turn engine off, brake holds as expected.
8. Pump brake while engine off, has some movement but is reasonably solid.
@potge I believe my bearings are fine.
Well it's fixed.
Andy
@J-SPEC sorted me out with 2 calipers with carriers. Just fitted them, bled the hell out of them. Got in the car, pumped the brakes up, went for a drive and what do you know... all good.
So it could have been my caliper rebuild but I actually think it was the carrier sliders being at fault. The one's from Andy were so much smoother. I could have sworn that they carriers seemed fine when I originally did the fronts but I guess when you haven't got anything to compare to...
Anyway, I'll put a TL:DR on my first post.
Saga over. Have a piccie... and no I haven't painted them, they turned up like that - now I have green on the front and red on the back :))
(https://i.ibb.co/BfJV10h/20230315-182535.jpg) (https://ibb.co/BfJV10h)
Keep it green as memento of good times
:) :) :)
Well done on your perseverance!
Having fought my sticky brakes, trying (and failing) to do a brake bleed with an Eezibleed spare tyre pressure system, and eventually doing a caliper rebuild for one of the fronts that had a seized piston, I understand how frustrating and scary it can be. As a real newbie to mechanics, I find dealing with critical components like brakes is a bit overwhelming at first, but the forum really helps get you through it with a bit of confidence.
Keeping it green is a very cool idea from
@shnazzle :))
@Trebordoody absolutely, and the help and encouragement from this club is fantastic as this thread shows. It also goes to show that sometimes you just need to replace more stuff than you first anticipated!
Quote from: shnazzle on March 15, 2023, 20:19Keep it green as memento of good times
:) :) :)
Also green for: let's goooo